A known stator of a rotary electrical machine is disclosed in, for example, JP4073705B (which will be hereinafter referred to as Reference 1). The stator according to Reference 1 includes plural split cores (core assemblies) around each of which a coil is wound and which are supported by a housing so as to form an annular shape. In the known stator, low-voltage-side and high-voltage-side terminals are attached to insulators insulating a laminated steel plate. Low-voltage-side and high-voltage-side end portions of the coil are connected to the low-voltage-side terminal and the high-voltage-side terminal, respectively. In addition, the low-voltage-side end portions of the respective coils of the split cores adjoining one another are electrically connected to one another by the low-voltage-side terminals. A groove portion, which is configured by a pair of vertical walls arranged next to each other so as to extend in a circumferential direction of the stator, is formed at an upper portion at an inner or outer circumferential side of each of the insulators that configure the split core. The grooves formed at the respective split cores adjoining one another are connected to one another, thereby forming a connected annular groove continuously extending in the circumferentially direction of the stator. The connected annular groove is filled with an insulating resin material.
In the stator according to Reference 1, the insulating resin material is filled in the connected annular groove formed at the inner or outer circumferential side of the insulator, entirely along the circumferential direction. Accordingly, an amount of the insulating resin material filled (used) in the connected annular groove is large, therefore increasing manufacturing costs of the stator. Further, a space filled with the insulating resin material is large; therefore, it is difficult for small portions of the connected annular groove to be filled with the insulating resin material. Accordingly, the connected annular groove may not be surely or fully filled with the insulating resin material, resulting in an insulation failure of ends of the coil. Consequently, an appropriate operation of the rotary electrical machine may be inhibited. JP2010-233405A (which will be hereinafter referred to as Reference 2) discloses a known stator of a rotary electrical machine, which avoids an inappropriate operation of a rotary electrical machine because of the foregoing insulation failure (see FIGS. 12 and 13).
As illustrated in FIGS. 12 and 13, a stator 1Z disclosed in Reference 2 includes a core unit 3Z in which plural split cores 4Z are arranged in an annular shape. Each of the plural split cores 4Z includes laminated steel plates 40, an insulator 41Z partially insulating the laminated steel plates 40, a coil 42 wound around the insulator 41Z, and a neutral point terminal 44. Low-voltage-side end portions 421 of the coils 42 respectively wound around the split cores 4Z are connected to one another by the neutral point terminals 44. A bus ring 5 retaining wire segments 53u, 53v, 53w is attached to an outer circumferential side of the core unit 3Z; thereby, the wire segments 53u, 53v, 53w are connected via electricity supply terminals 54 to high-voltage-side end portions 422 of the coils 42, respectively.
Radially outward terminal-accommodating boxes 511 opened to an upper side of the stator 1Z and to the split cores 4Z is provided in a position facing the split cores 4Z that are arranged at an upper side of the bus ring 5 in a state where the bus ring 5 is attached to the core unit 3Z. Resin boxes 43Z are arranged at an upper side of the insulators 41Z of the split cores 4Z, respectively. The resin boxes 43Z include radially inward terminal-accommodating boxes 431Z, respectively, opened to the upper side of the stator 1Z and to the radially outward terminal-accommodating boxes 511. The radially outward terminal-accommodating boxes 511 and the radially inward terminal-accommodating boxes 431Z are aligned to along a circumferential direction of the core unit 3Z so as to face one another, thereby forming plural terminal accommodating boxes 6Z opened to the upper side of the stator 1Z. A radially inward flange 411Z and a radially outward flange 413Z that extend in a vertical direction of the stator 1Z and in the circumferential direction of the core unit 3Z are formed at the insulator 41Z so as to be positioned at an inner circumferential side of the core unit 3Z and at the outer circumferential side of the core unit 3Z in a state where the coil 42 of the insulator 41Z is arranged between the radially inward and outward sides of the core unit 3Z. Each of the resin boxes 43Z is supported from a lower side thereof by the radially inward flange 411Z and the radially outward flange 413Z.
The low-voltage-side end portion 421 of the coil 42 is arranged at an upper side of side walls of the radially inward terminal-accommodating box 431Z so as to extend between the side walls facing each other in a circumferential direction of the radially inward terminal-accommodating box 431Z. A pair of wire engagement portions 414Z protruding toward an upper side of the split core 4Z and separating from each other in the circumferential direction of the core unit 3Z is formed at an upper end of the radially outward flange 413Z of the insulator 41Z. The high-voltage-side end portion 422 of the coil 42 is provided so as to extend between the pair of wire engagement portions 414Z. An insulating resin material is filled in each of the terminal accommodating boxes 6Z in a state where a connected portion between the neutral point terminal 44 and the low-voltage-side end portion 421 of the coil 42 and a connected portion between the electricity supply terminal 54 and the high-voltage-side end portion 422 of the coil 42 are accommodated in the terminal accommodating box 6Z. Two protruding walls 438Z protruding toward a lower side of the split core 4 are formed at a radially inward side of a bottom portion 435Z of the resin box 43Z. Engagement projections 438Za protruding radially inwardly are formed at respective lower ends of the protruding walls 438Z. Two engagement holes 412Z are formed at an upper portion of the radially inward flange 411Z of the insulator 41Z so as to penetrate through the radially inward flange 411Z. The engagement projections 438Za of the protruding walls 438Z, respectively, are inserted in the engagement holes 412Z; thereafter, the resin box 43Z is rotated about the both engagement holes 412Z from the upper side to the lower side of the split core 4. Therefore, the resin box 43Z is attached to the insulator 41Z. The bottom portion 435Z of the radially inward terminal-accommodating box 431Z includes an extending bottom portion 436Z that protrudes radially outwardly from the bottom portion 435Z. In a state where the resin box 43Z is in an attached position relative to the split core 4Z, the extending bottom portion 436Z is located adjacent to a bottom portion 521 (holding flange) of the radially outward terminal-accommodating box 511 to the extent that an outflow of the insulating resin material may not occur.
According to the stator 1Z disclosed in Reference 2, the resin box 43Z is rotated or moved from the upper side to the lower side of the split core 4Z to be therefore attached to the insulator 41Z. In such attaching method to attach the resin box 43Z to the insulator 41Z, an appropriate clearance needs to be provided between the extending bottom portion 436Z of the radially inward terminal-accommodating box 431Z and the bottom portion 521 of the radially outward terminal-accommodating box 511. For example, in a case where the clearance is small, the resin box 43Z may not be smoothly or easily attached to the insulator 41Z because of a contact between components. Further, for example, in a case where the clearance is large, the insulating resin material may flow out from the clearance.
In addition, according to the stator 1Z disclosed in Reference 2, the attaching operation of the resin box 43Z to the insulator 41Z is conducted in a state where the high-voltage-side end portion 422 of the coil 42 is positioned to extend between the pair of wire engagement portions 414Z. Therefore, it is necessary for the resin box 43Z to be moved from the upper side to the lower side of the split core 4Z in a state where the extending bottom portion 436Z of the radially inward terminal-accommodating box 431Z is kept non-contact with the high-voltage-side end portion 422. Consequently, the resin box 43Z may not be easily attached to the insulator 41Z.
A need thus exists for a stator of a rotary electrical machine, which is not susceptible to the drawbacks mentioned above.